package com.atguigu.facade;

/**
 * @program: design-patterns
 * @author: yangshen
 * @description: 子系统4：屏幕
 * @create: 2022-02-21 14:35
 **/
public class Screen {
    /**
     * 单例模式，使用饿汉式
     */
    private static Screen instance = new Screen();

    public static Screen getInstance(){
        return instance;
    }

    public void up(){
        System.out.println("屏幕 上升");
    }

    public void down(){
        System.out.println("屏幕 下降");
    }
}
